//https://github.com/douglascrockford/JSON-js
//  json2.js
//  2017-06-12
//  Public Domain.
//  NO WARRANTY EXPRESSED OR IMPLIED. USE AT YOUR OWN RISK.

//  USE YOUR OWN COPY. IT IS EXTREMELY UNWISE TO LOAD CODE FROM SERVERS YOU DO
//  NOT CONTROL.
const JSON = {};

export default JSON;

let rx_one = /^[\],:{}\s]*$/;
let rx_two = /\\(?:["\\\/bfnrt]|u[0-9a-fA-F]{4})/g;
let rx_three = /"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g;
let rx_four = /(?:^|:|,)(?:\s*\[)+/g;
let rx_escapable = /[\\"\u0000-\u001f\u007f-\u009f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g;
let rx_dangerous = /[\u0000\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g;

function f(n) {
	// Format integers to have at least two digits.
	return(n < 10) ?
		"0" + n :
		n;
}

function this_value() {
	return this.valueOf();
}

if(typeof Date.prototype.toJSON !== "function") {

	Date.prototype.toJSON = function() {
		return isFinite(this.valueOf()) ?
			(
				this.getUTCFullYear() +
				"-" +
				f(this.getUTCMonth() + 1) +
				"-" +
				f(this.getUTCDate()) +
				"T" +
				f(this.getUTCHours()) +
				":" +
				f(this.getUTCMinutes()) +
				":" +
				f(this.getUTCSeconds()) +
				"Z"
			) :
			null;
	};

	Boolean.prototype.toJSON = this_value;
	Number.prototype.toJSON = this_value;
	String.prototype.toJSON = this_value;
}

let gap;
let indent;
let meta;
let rep;

function quote(string) {

	// If the string contains no control characters, no quote characters, and no
	// backslash characters, then we can safely slap some quotes around it.
	// Otherwise we must also replace the offending characters with safe escape
	// sequences.

	rx_escapable.lastIndex = 0;
	return rx_escapable.test(string) ?
		"\"" + string.replace(rx_escapable, function(a) {
			let c = meta[a];
			return typeof c === "string" ?
				c :
				"\\u" + ("0000" + a.charCodeAt(0).toString(16)).slice(-4);
		}) + "\"" :
		"\"" + string + "\"";
}

function str(key, holder) {
	// Produce a string from holder[key].
	let i; // The loop counter.
	let k; // The member key.
	let v; // The member value.
	let length;
	let mind = gap;
	let partial;
	let value = holder[key];

	// If the value has a toJSON method, call it to obtain a replacement value.
	if(
		value &&
		typeof value === "object" &&
		typeof value.toJSON === "function"
	) {
		value = value.toJSON(key);
	}

	// If we were called with a replacer function, then call the replacer to
	// obtain a replacement value.

	if(typeof rep === "function") {
		value = rep.call(holder, key, value);
	}

	// What happens next depends on the value's type.

	switch(typeof value) {
		case "string":
			return quote(value);
		case "number":
			// JSON numbers must be finite. Encode non-finite numbers as null.
			return(isFinite(value)) ?
				String(value) :
				"null";

		case "boolean":
		case "null":
			// If the value is a boolean or null, convert it to a string. Note:
			// typeof null does not produce "null". The case is included here in
			// the remote chance that this gets fixed someday.
			return String(value);

			// If the type is "object", we might be dealing with an object or an array or
			// null.
		case "object":
			// Due to a specification blunder in ECMAScript, typeof null is "object",
			// so watch out for that case.
			if(!value) {
				return "null";
			}

			// Make an array to hold the partial results of stringifying this object value.

			gap += indent;
			partial = [];
			// Is the value an array?
			if(Object.prototype.toString.apply(value) === "[object Array]") {

				// The value is an array. Stringify every element. Use null as a placeholder
				// for non-JSON values.
				length = value.length;
				for(i = 0; i < length; i += 1) {
					partial[i] = str(i, value) || "null";
				}
				// Join all of the elements together, separated with commas, and wrap them in
				// brackets.

				v = partial.length === 0 ?
					"[]" :
					gap ?
					(
						"[\n" +
						gap +
						partial.join(",\n" + gap) +
						"\n" +
						mind +
						"]"
					) :
					"[" + partial.join(",") + "]";
				gap = mind;
				return v;
			}

			// If the replacer is an array, use it to select the members to be stringified.
			if(rep && typeof rep === "object") {
				length = rep.length;
				for(i = 0; i < length; i += 1) {
					if(typeof rep[i] === "string") {
						k = rep[i];
						v = str(k, value);
						if(v) {
							partial.push(quote(k) + (
								(gap) ?
								": " : ":"
							) + v);
						}
					}
				}
			} else {
				// Otherwise, iterate through all of the keys in the object.
				for(k in value) {
					if(Object.prototype.hasOwnProperty.call(value, k)) {
						v = str(k, value);
						if(v) {
							partial.push(quote(k) + (
								(gap) ?
								": " :
								":"
							) + v);
						}
					}
				}
			}

			// Join all of the member texts together, separated with commas,
			// and wrap them in braces.

			v = partial.length === 0 ?
				"{}" : gap ?
				"{\n" + gap + partial.join(",\n" + gap) + "\n" + mind + "}" :
				"{" + partial.join(",") + "}";
			gap = mind;
			return v;
	}
}

// If the JSON object does not yet have a stringify method, give it one.
if(typeof JSON.stringify !== "function") {
	meta = { // table of character substitutions
		"\b": "\\b",
		"\t": "\\t",
		"\n": "\\n",
		"\f": "\\f",
		"\r": "\\r",
		"\"": "\\\"",
		"\\": "\\\\"
	};
	JSON.stringify = function(value, replacer, space) {

		// The stringify method takes a value and an optional replacer, and an optional
		// space parameter, and returns a JSON text. The replacer can be a function
		// that can replace values, or an array of strings that will select the keys.
		// A default replacer method can be provided. Use of the space parameter can
		// produce text that is more easily readable.

		let i;
		gap = "";
		indent = "";
		// If the space parameter is a number, make an indent string containing that
		// many spaces.
		if(typeof space === "number") {
			for(i = 0; i < space; i += 1) {
				indent += " ";
			}

			// If the space parameter is a string, it will be used as the indent string.

		} else if(typeof space === "string") {
			indent = space;
		}

		// If there is a replacer, it must be a function or an array.
		// Otherwise, throw an error.

		rep = replacer;
		if(replacer && typeof replacer !== "function" && (
				typeof replacer !== "object" ||
				typeof replacer.length !== "number"
			)) {
			throw new Error("JSON.stringify");
		}

		// Make a fake root object containing our value under the key of "".
		// Return the result of stringifying the value.

		return str("", {
			"": value
		});
	};
}

// If the JSON object does not yet have a parse method, give it one.

if(typeof JSON.parse !== "function") {
	JSON.parse = function(text, reviver) {
		// The parse method takes a text and an optional reviver function, and returns
		// a JavaScript value if the text is a valid JSON text.
		let j;

		function walk(holder, key) {
			// The walk method is used to recursively walk the resulting structure so
			// that modifications can be made.
			let k;
			let v;
			let value = holder[key];
			if(value && typeof value === "object") {
				for(k in value) {
					if(Object.prototype.hasOwnProperty.call(value, k)) {
						v = walk(value, k);
						if(v !== undefined) {
							value[k] = v;
						} else {
							delete value[k];
						}
					}
				}
			}
			return reviver.call(holder, key, value);
		}

		// Parsing happens in four stages. In the first stage, we replace certain
		// Unicode characters with escape sequences. JavaScript handles many characters
		// incorrectly, either silently deleting them, or treating them as line endings.
		text = String(text);
		rx_dangerous.lastIndex = 0;
		if(rx_dangerous.test(text)) {
			text = text.replace(rx_dangerous, function(a) {
				return(
					"\\u" +
					("0000" + a.charCodeAt(0).toString(16)).slice(-4)
				);
			});
		}

		// In the second stage, we run the text against regular expressions that look
		// for non-JSON patterns. We are especially concerned with "()" and "new"
		// because they can cause invocation, and "=" because it can cause mutation.
		// But just to be safe, we want to reject all unexpected forms.

		// We split the second stage into 4 regexp operations in order to work around
		// crippling inefficiencies in IE's and Safari's regexp engines. First we
		// replace the JSON backslash pairs with "@" (a non-JSON character). Second, we
		// replace all simple value tokens with "]" characters. Third, we delete all
		// open brackets that follow a colon or comma or that begin the text. Finally,
		// we look to see that the remaining characters are only whitespace or "]" or
		// "," or ":" or "{" or "}". If that is so, then the text is safe for eval.

		if(
			rx_one.test(
				text
				.replace(rx_two, "@")
				.replace(rx_three, "]")
				.replace(rx_four, "")
			)
		) {

			// In the third stage we use the eval function to compile the text into a
			// JavaScript structure. The "{" operator is subject to a syntactic ambiguity
			// in JavaScript: it can begin a block or an object literal. We wrap the text
			// in parens to eliminate the ambiguity.
			j = eval("(" + text + ")");
			// In the optional fourth stage, we recursively walk the new structure, passing
			// each name/value pair to a reviver function for possible transformation.

			return(typeof reviver === "function") ?
				walk({
					"": j
				}, "") : j;
		}
		// If the text is not JSON parseable, then a SyntaxError is thrown.
		throw new SyntaxError("JSON.parse");
	};
}